[blubomber]

One more note on the motor

The YH code 428 360 hp engine is a small valve design. They produce decent power and lots of torque but are not really muscle car motors despite their displacement. They are 2 bolt mains. These cars usually came with a 3:08 rear end.

The YK code 428 is a true muscle motor with drilled in valve stems, large valves, higher compression; 10.75:1, long branch exhaust manifolds, larger exhaust pipes, competition cam, high capacity oil pump, stronger distributor advance springs. Listed at 390 hp they were probably more like 430 hp. This is a differnt engine than then YH motor espite their identical displacments.

These YK motors were not available to the A body or Firebird cars due to the GM restriction on 400 motors or smaller for all A F body cars except the Corvette. This was lifted for 1970 to combat the large engines used in Ford and Dodge/Plymouth cars. In 1970 you could get the 455 in mid-size GM cars. This situation has restricted the limited the disireability of the 428 for muscle cars. 455's are more desireable in general. You can get year correct 455's for $650-$850.